1. Technical Field
The present disclosure relates to a polarizer used in a liquid crystal display screen with touch sensing capability.
2. Description of Related Art
A conventional liquid crystal display screen for a liquid crystal display (LCD), according to the prior art, generally includes a first polarizer, a thin film transistor (TFT) panel, a first alignment layer, a liquid crystal layer, a second alignment layer, a common electrode layer (e.g., an indium tin oxide (ITO) layer), an upper board, and a second polarizer. The TFT panel includes a plurality of pixel electrodes. Polarizing directions of the first and second polarizers are perpendicular to each other. When a voltage is applied between the pixel electrode and the common electrode layer, the liquid crystal molecules in the liquid crystal layer between the first alignment layer and the second alignment layer align along a same direction to polarize the light beams by the first polarizer irradiate on the second polarizer directly without rotation, and the polarized light beams cannot pass through the first polarizer. Without a voltage applied to the pixel electrode and the common electrode layer, the polarized light beams rotated by the liquid crystal molecules can pass through the second polarizer. Selectively applying voltages between different pixel electrodes and the common electrode layer can control the on and off of different pixels, thus displaying images.
A conventional polarizing layer is made by using a transparent polymer film (e.g., PVA film) to absorb dichroic material, to let the dichroic material infiltrated into the transparent polymer film, and extruding the transparent polymer film to align the dichroic material in one direction. A conventional polarizer includes not only the polarizing layer but also protective layers, adhesive layer, separating layer covered on two opposite surfaces of the polarizing layer. During the manufacturing of the liquid crystal display screen, the second polarizer is directly attached to a top surface of the upper board.
Following the advancement in recent years of various electronic apparatuses, such as mobile phones, car navigation systems and the like, toward high performance and diversification, there has been continuous growth in the number of electronic apparatuses equipped with optically transparent touch panels in front of their respective display devices (e.g., liquid crystal display screen). The touch panel is commonly attached to the top surface of the second polarizer. However, this arrangement will increase a thickness of the electronic apparatuses. Further, the touch panel and the second polarizer are individually manufactured and assembled, which increases the complication of the manufacturing process, and increases a cost for production.
What is needed, therefore, is to provide a polarizer capable of sensing touches occurred thereon meanwhile polarizing lights, thus the liquid crystal display screen using the polarizer does not need to have a separate touch panel.